This link is for 12 cartridges for 8.99 with free delivery but the important thing is that the seller is actually Buytech (Seller ID is buyyourinkfromme) which has been listed many times before. There are loads of other makes and models covered in their eBay shop.

If you go direct to the Buytech site this pack is 7.99 + P&P = 10.28. So this eBay deal is 75p per cartridge rather than 85p.

(It's not that obvious it's Buytech at first, but the postal address and phone number are very similar and the invoice after payment actually states Buytech. Also the product photos are from the Buytech site.)